ADTRAN 1200218L1, User Manual

Page: 62 / 122

Chapter 4. Status
4-6 OSU 300 User Manual 61200663L1-1
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HSSI Interface Leads
TA (terminal available)
Asserted by the DTE to indicate readiness to transmit data.
CA (communications equipment available)
Asserted by the OSU 300 to indicate readiness to transmit data.
LA (loopback circuit A)
The condition reflected by this lead is dependent upon the LB lead.
See Table 4-1.
LB (loopback circuit B)
The condition reflected by this lead is dependent upon the LA lead.
See Table 4-1.
LC (loopback circuit C)
Asserted by the unit to request a loopback from the DTE.
TM (test mode)
Asserted by the OSU 300 when either the network or the port is
being tested.
When a DSX-1 port is enabled but is not attached to a DTE device, the
OSU 300 will transmit an unframed all ones condition (blue alarm) to
the remote site.
Both TA and CA must be on before data will flow.
Table 4-1. LA and LB Leads
LA LB Condition
Off Off No test (normal)
On Off Local line loopback
Off On Remote line loopback
On On Local DTE loopback